MDRO Prevention Bundle in Nursing Homes: A Randomized Trial

In keeping with our long-term care theme (more on this later in the week), there is a new trial published in JAMA Internal Medicine by Lona Mody and colleagues at the University of Michigan. The team completed a cluster-randomized trial of a bundled intervention to prevent MDROs in nursing homes. Specifically, residents with indwelling urinary catheters, feeding tubes or both in 6 nursing homes were randomized to a targeted infection program (TIP) bundle that included (1) preemptive barrier precautions; (2) active surveillance for MDROs (baseline, day 15 and monthly at nares, oropharynx, feeding tube, supra-pubic catheter, groin, peri-rectal, and wound sites) and infections, with data feedback; and (3) NH staff education on key infection prevention practices, including minimum criteria for initiating antibiotics, and hand hygiene promotion. Inclusion required a signed inform consent. Six other nursing homes served as controls.

The outcomes assessed were quite broad. The primary outcome was "overall MDRO prevalence density rate, defined as each participant’s total number of MDRO-positive anatomic sites across all MDROs per visit averaged over the duration of his or her participation." This would result in residents "with persistent MDRO colonization (having) a higher prevalence than someone with intermittent or no colonization" and residents colonized at more sites (up to seven were tested) having a higher prevalence. Secondary outcomes included new MDRO acquisition and device-associated HAI both with 1000 device-day denominators.

For the primary outcome, 27% of swabs were positive in the intervention NH residents while 33% were positive in the control NH residents. The adjusted rate ratio was significant 0.77 (0.62-0.94). This outcome seems largely driven by lower MRSA colonization in residents with urinary catheters, feeding tubes, or both and lower ceftazidime-resistant GNR colonization in residents with urinary catheters in the intervention NHs. However, rates of VRE were higher in the feeding tube requiring residents but this increase was not significant. (see Table 3) Interestingly, new MRSA acquisition rates were lower in the intervention NH residents (see Table 4, below) and first new CAUTI rates were also lower in the intervention NH residents, HR 0.54 (0.30-0.97).

Overall, an important study and one that should be read closely. Clearly this was a very difficult RCT to undertake, especially with informed consent, and the research team should be congratulated. The primary outcome of MDRO prevalence density rate is an interesting choice and the authors make a compelling argument for why they chose it. However, it is unclear if the interventions in the TIP bundle are major components in the causal pathway for limiting MDRO colonization density or reducing CAUTI. However, the lower MRSA acquisition rate in the intervention NHs is an important outcome and does fit with how we expect barrier precautions to work. Minor quibbles aside, this RCT should be discussed widely and many components of it are worth testing in other settings in future trials. 

Evidence-based infection prevention: A modest proposal

This is a special guest post by David Hartley, PhD who is a Research Associate Professor in the department of Microbiology and Immunology at the Georgetown University Medical Center.

I don't know if there are dedicated courses in schools of medicine and nursing in the US devoted specifically to hospital infection control and prevention, but if there are, I haven't found them. There are lots of training courses offered by trade societies, and many of these are great at conveying procedure, technique, and rationale, but I'm thinking about academic, didactic courses presenting a comprehensive picture of what is known, how it is known, and emerging ideas about infection control and prevention. Any science-based course should expose the learner to the continuum of theory, evidence, and practice. I think it could be done in a semester.

How best to approach such a course needs to be discussed and worked out, but one might, for example, begin with a survey of what we know about what people are commonly colonized and infected with, and how they got that way. This would entail examination of aerosol, alimentary, percutaneous, and other infectious pathways as appropriate, focusing upon important pathogens of concern in healthcare facilities. It could then go on to examine microbial life histories along each route of infection, and how common hospital practices act synergistically or antagonistically with each such route. Host response to infection would be important to cover, and a quantitative epidemiological component should also be included. To tie everything together, learners could undertake a final project assessing what current infection prevention practices are evidence-based and which aren't, and what evidence might be useful for better informing infection control practice. Such a course might be entitled Infection Control and Prevention: From Science to Practice. If done well, the course could help to train learners to think about infection within the context of a coherent, interconnected, evidence-based picture.

By and large, it seems like such an expansive, theoretical picture of hospital infection control and prevention is lacking at present. There are mathematical and computer models of varying complexity and realism that together have led to insights, though how to generalize and apply these is sometimes unclear to preventionists. There are also rules and guidelines, though some (many?) are not as well studied as one might expect (e.g., handwashing and contact precautions). There are increasing numbers of studies suggesting that this intervention works here and that intervention works there, but understanding how all this knowledge fits together to inform thinking and practice, in a truly robust way, remains elusive. A systems approach to both teaching and thinking about infection prevention may prepare the next generation of researchers and clinicians to think more holistically and progressively about infection in healthcare environments.

(More) Other Advice to Young Epidemiologists

1) Don't call anyone an idiot.
2) Question subjects carefully.



For "other advice" see ICHE 2006